This invention relates to waterborne dispersions of epoxidized polydiene block polymers. More specifically, the invention relates to waterborne dispersions of such polymers and amino resins which can be crosslinked to make cured films, coatings, adhesives, sealants, caulks, binders and modifiers for asphalt.
Epoxidized polydiene polymers have been disclosed recently in U.S. Pat. Nos. 5,229,464 and 5,247,026. These are relatively low epoxy content polymers. Higher epoxy content polymers are described in copending, commonly assigned United States patent application Ser. No. 228,047, filed Apr. 15, 1994, entitled "Epoxidized Low Viscosity Rubber." It has been shown that such polymers are useful in high solids, solvent-borne adhesives and coatings and that formulations containing these polymers and a cationic photoinitiator can be cured via ultraviolet radiation. It has also been shown that formulations containing these polymers, a melamine resin, and an acid catalyst can be cured by baking under normal bake conditions.
Although this high solids technology is of great value, it is true that if such polymers could be dispersed in water, the utility of these polymers would be greatly broadened. This would allow preparation of low viscosity, waterborne formulations having very low volatile organic compound (VOC) contents. By adding waterborne epoxidized polydiene polymer dispersions to other water-based products having compatible surfactant systems, these polymers could be used to modify other types of resins and this could be done without concern about phase separation due to incompatibility of the epoxidized polydiene polymers and solvent-based resins.
It is one object of the present invention to provide a crosslinkable waterborne dispersion of epoxidized polydiene polymers and amino resins. Another object of this invention is to provide a method for maldng such crosslinkable waterborne dispersions.